We consider the relationship between string theory and currently proposed models of extended inflation. In doing so, we discuss the conformal actions in string theory and in Jordan-Brans-Dicke gravity. We show explicitly the equivalence of pictures in which either gauge or gravitational couplings are changing with time. We demonstrate that the existence of the dilation in string theory does not naturally lead to extended inflation as currently discussed. We also discuss the resolution of the graceful exit problem of old inflation in Einstein gravity using either power-law inflation, or exponential inflation with a changing bubble formation rate.
Bibliographical noteFunding Information:
The work of B.A.C. was supported in part by the Natural Sciences and Engineering Research Council of Canada. The work of K.A.O. was supported in part by DOE grant DE-AC02-83ER-40105 and by a Presidential Young Investigator Award.